21530130 has 32 divisors (see below), whose sum is σ = 51948864. Its totient is φ = 5710656.

The previous prime is 21530129. The next prime is 21530147. The reversal of 21530130 is 3103512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4089 + ... + 7731.

It is an arithmetic number, because the mean of its divisors is an integer number (1623402).

Almost surely, 2^21530130 is an apocalyptic number.

21530130 is an abundant number, since it is smaller than the sum of its proper divisors (30418734).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21530130 is a wasteful number, since it uses less digits than its factorization.

21530130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3850.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21530130 is about 4640.0571117175. The cubic root of 21530130 is about 278.1947206432.

Adding to 21530130 its reverse (3103512), we get a palindrome (24633642).

The spelling of 21530130 in words is "twenty-one million, five hundred thirty thousand, one hundred thirty".